Listing 1: Calculating the Total I/O for Each Database
SELECT
DB_NAME(database_id) AS database_name,
CAST(SUM(num_of_bytes_read + num_of_bytes_written) / 1048576.
AS DECIMAL(12, 2)) AS io_in_mb
FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS DM_IO_Stats
GROUP BY database_id;
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